Your mission, should you choose to accept it, is to find names for any or all of these fine upstanding purveyors of justice.

From left to right, we have:

The sergeant, a no-nonsense kind of guy. (No first or last name yet.)

Private Andir, a keen fellow. (Could still use a first name.)

Corporal Phidega, somewhat less keen. (Could still use a first name.)

The sketch artist, last seen here. (No first or last name yet, but nicknamed "Doc.")

The lady corporal, deliverer of exposition. (No first or last name yet.)

And a naive young recruit with freckles. (No first or last name. I wonder if he'll need them?)

Feel free to suggest first names, last names, or both!
Winners will receive high-fives and an honorable mention on the cast page. _________________"The one concession a sane man will never yield the universe is that of considering it seriously."
~ James Branch Cabell

The Smart Guy: Winston Phineas (I greatly agree with Seamstress24601, who postulated above that he acts like a Winston.)

The Chick: Julia Phillips (She just seems greatly like a Julia to me.)

The Redshirt: Acacius Ernest (A big, pompous name for a meek little guy. Also, "Acacius" is the Latinization of the Greek name "Akakios," which means "innocent" or "not evil." I guess this translates to "meek and naive.")

I love behindthename.com, for all your naming difficulties! (This is how I got Keenan for keen ol' Andir and Acacius for the poor innocent redshirt.)

For some reason, Corporal Phineas Phidega just keeps bouncing around my head.
Hopefully I'll come up with more later!_________________The people who look at you strangely when you suddenly break out into song and dance are just jealous that they were not cast in a staring role.

Smart Guy: Bradypus. It is a genus of sloth, but certainly suited for a smart guy who knows smart things. For a species name pun, possible surnames include Tridactylus, Torquatus, Variegatus, or Pygmaeus. Or, if you want a longer name and something retro, his full name could also be: Bradypus Cuculliger Cuculliger (with two Cuculligers), Bradypus Infuscatus Flaccidus, or Bradypus Griseus Griseus (with two Grisei).
If you really don't want him to be Bradypus Tridactylus, he could be Art Sketcher.

As for the others:
Chick: Expositia. If somebody can suggest something similar to Expositia, I'll go with that too. Or Bradypoda. Maybe Bradypoda Xenarthra? Family puns are much harder than genus puns.
Hero: He could also be called "Sarge Ant" or "Sarge Ent". Or Bradypus.
Redshirt: He could also be Baron Red, or Eric the Redshirt. Also, I once had a dream where Batman was hired to protect a fashion designer named Redshir who had reason to believe he was doomed to die because he wore red shirts, so Redshir, or Redshire. Or Bradypus.
Lancer: It's hard to top Keenan. Lance Andir? Andreas Andir? Andrew Andir: Andreas? Keen? Maybe not as good as Keenan. Or he could be Bradypus.

But if this were a democratic option, I'd vote Keenan Andir. Nice choice, landscapeofalie!